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    <title>Document</title>
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<body>
    <button>点击</button>
    <script> 
        class Star {
            constructor(uname, age) {
                this.uname = uname;
                this.age = age;
            }
            sing() {
                console.log('hi');
                console.log(uname);
            }
        }
        new Star('林俊杰', 20);

        // 1. 在 ES6 中类没有变量提升，所以必须先定义类，才能通过类实例化对象
        // 2. 类里面的共有的属性和方法一定要加this使用

    </script>
</body>

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